-- Load support for MT game translation.
local S = minetest.get_translator("boats")

--
-- Helper functions
--

local function is_water(pos)
   local nn = minetest.get_node(pos).name
   return minetest.get_item_group(nn, "water") ~= 0
end


local function get_velocity(v, yaw, y)
   local x = -math.sin(yaw) * v
   local z =  math.cos(yaw) * v
   return {x = x, y = y, z = z}
end


local function get_v(v)
   return math.sqrt(v.x ^ 2 + v.z ^ 2)
end

--
-- Boat entity
--

local boat = {
   initial_properties = {
      physical = true,
      -- Warning: Do not change the position of the collisionbox top surface,
      -- lowering it causes the boat to fall through the world if underwater
      collisionbox = {-0.5, -0.35, -0.5, 0.5, 0.3, 0.5},
      visual = "mesh",
      mesh = "boats_boat.obj",
      textures = {"default_wood.png"},
   },

   driver = nil,
   v = 0,
   last_v = 0,
   removed = false,
   auto = false
}


function boat.on_rightclick(self, clicker)
   if not clicker or not clicker:is_player() then
      return
   end
   local name = clicker:get_player_name()
   if self.driver and name == self.driver then
      self.driver = nil
      self.auto = false
      clicker:set_detach()
      player_api.player_attached[name] = false
      player_api.set_animation(clicker, "stand" , 30)
      local pos = clicker:get_pos()
      pos = {x = pos.x, y = pos.y + 0.2, z = pos.z}
      minetest.after(0.1, function()
         clicker:set_pos(pos)
      end)
   elseif not self.driver then
      local attach = clicker:get_attach()
      if attach and attach:get_luaentity() then
         local luaentity = attach:get_luaentity()
         if luaentity.driver then
            luaentity.driver = nil
         end
         clicker:set_detach()
      end
      self.driver = name
      clicker:set_attach(self.object, "",
         {x = 0.5, y = 1, z = -3}, {x = 0, y = 0, z = 0})
      player_api.player_attached[name] = true
      minetest.after(0.2, function()
         player_api.set_animation(clicker, "sit" , 30)
      end)
      clicker:set_look_horizontal(self.object:get_yaw())
   end
end


-- If driver leaves server while driving boat
function boat.on_detach_child(self, child)
   self.driver = nil
   self.auto = false
end


function boat.on_activate(self, staticdata, dtime_s)
   --self.object:set_armor_groups({immortal = 1})
   if staticdata then
      self.v = tonumber(staticdata)
   end
   self.last_v = self.v
   self.object:set_hp(200)
end


function boat.get_staticdata(self)
   return tostring(self.v)
end


function boat.on_punch(self, puncher, time_from_last_punch, tool_capabilities, dir, damage)
   if not puncher or not puncher:is_player() or self.removed then
      return
   end

   local name = puncher:get_player_name()
   if self.driver and name == self.driver then
      self.driver = nil
      puncher:set_detach()
      player_api.player_attached[name] = false
   end
   if not self.driver then
      self.removed = true
      local inv = puncher:get_inventory()
      if not (creative and creative.is_enabled_for
            and creative.is_enabled_for(name))
            or not inv:contains_item("main", "boats:boat") then
         local leftover = inv:add_item("main", "boats:boat")
         -- if no room in inventory add a replacement boat to the world
         if not leftover:is_empty() then
            minetest.add_item(self.object:get_pos(), leftover)
         end
      end
      -- delay remove to ensure player is detached
      minetest.after(0.1, function()
         self.object:remove()
      end)
   end
end


function boat.on_step(self, dtime)
   self.v = get_v(self.object:get_velocity()) * math.sign(self.v)
   if self.driver then
      local driver_objref = minetest.get_player_by_name(self.driver)
      if driver_objref then
         local ctrl = driver_objref:get_player_control()
         if ctrl.up and ctrl.down then
            if not self.auto then
               self.auto = true
               minetest.chat_send_player(self.driver, S("Boat cruise mode on"))
            end
         elseif ctrl.down then
            self.v = self.v - dtime * 2.0
            if self.auto then
               self.auto = false
               minetest.chat_send_player(self.driver, S("Boat cruise mode off"))
            end
         elseif ctrl.up or self.auto then
            self.v = self.v + dtime * 2.0
         end
         if ctrl.left then
            if self.v < -0.001 then
               self.object:set_yaw(self.object:get_yaw() - dtime * 0.9)
            else
               self.object:set_yaw(self.object:get_yaw() + dtime * 0.9)
            end
         elseif ctrl.right then
            if self.v < -0.001 then
               self.object:set_yaw(self.object:get_yaw() + dtime * 0.9)
            else
               self.object:set_yaw(self.object:get_yaw() - dtime * 0.9)
            end
         end
      end
   end
   local velo = self.object:get_velocity()
   if self.v == 0 and velo.x == 0 and velo.y == 0 and velo.z == 0 then
      self.object:set_pos(self.object:get_pos())
      return
   end
   -- We need to preserve velocity sign to properly apply drag force
   -- while moving backward
   local drag = dtime * math.sign(self.v) * (0.01 + 0.0796 * self.v * self.v)
   -- If drag is larger than velocity, then stop horizontal movement
   if math.abs(self.v) <= math.abs(drag) then
      self.v = 0
   else
      self.v = self.v - drag
   end

   local p = self.object:get_pos()
   p.y = p.y - 0.5
   local new_velo
   local new_acce = {x = 0, y = 0, z = 0}
   if not is_water(p) then
      local nodedef = minetest.registered_nodes[minetest.get_node(p).name]
      if (not nodedef) or nodedef.walkable then
         self.v = 0
         new_acce = {x = 0, y = 1, z = 0}
      else
         new_acce = {x = 0, y = -9.8, z = 0}
      end
      new_velo = get_velocity(self.v, self.object:get_yaw(),
         self.object:get_velocity().y)
      self.object:set_pos(self.object:get_pos())
   else
      p.y = p.y + 1
      if is_water(p) then
         local y = self.object:get_velocity().y
         if y >= 5 then
            y = 5
         elseif y < 0 then
            new_acce = {x = 0, y = 20, z = 0}
         else
            new_acce = {x = 0, y = 5, z = 0}
         end
         new_velo = get_velocity(self.v, self.object:get_yaw(), y)
         self.object:set_pos(self.object:get_pos())
      else
         new_acce = {x = 0, y = 0, z = 0}
         if math.abs(self.object:get_velocity().y) < 1 then
            local pos = self.object:get_pos()
            pos.y = math.floor(pos.y) + 0.5
            self.object:set_pos(pos)
            new_velo = get_velocity(self.v, self.object:get_yaw(), 0)
         else
            new_velo = get_velocity(self.v, self.object:get_yaw(),
               self.object:get_velocity().y)
            self.object:set_pos(self.object:get_pos())
         end
      end
   end
   self.object:set_velocity(new_velo)
   self.object:set_acceleration(new_acce)
end


minetest.register_entity("boats:boat", boat)


minetest.register_craftitem("boats:boat", {
   description = S("Boat"),
   inventory_image = "boats_inventory.png",
   wield_image = "boats_wield.png",
   wield_scale = {x = 2, y = 2, z = 1},
   liquids_pointable = true,
   groups = {flammable = 2},

   on_place = function(itemstack, placer, pointed_thing)
      local under = pointed_thing.under
      local node = minetest.get_node(under)
      local udef = minetest.registered_nodes[node.name]
      if udef and udef.on_rightclick and
            not (placer and placer:is_player() and
            placer:get_player_control().sneak) then
         return udef.on_rightclick(under, node, placer, itemstack,
            pointed_thing) or itemstack
      end

      if pointed_thing.type ~= "node" then
         return itemstack
      end
      if not is_water(pointed_thing.under) then
         return itemstack
      end
      pointed_thing.under.y = pointed_thing.under.y + 0.5
      boat = minetest.add_entity(pointed_thing.under, "boats:boat")
      if boat then
         if placer then
            boat:set_yaw(placer:get_look_horizontal())
         end
         local player_name = placer and placer:get_player_name() or ""
         if not (creative and creative.is_enabled_for and
               creative.is_enabled_for(player_name)) then
            itemstack:take_item()
         end
      end
      return itemstack
   end,
})


minetest.register_craft({
   output = "boats:boat",
   recipe = {
      {"",           "",           ""          },
      {"group:wood", "",           "group:wood"},
      {"group:wood", "group:wood", "group:wood"},
   },
})

minetest.register_craft({
   type = "fuel",
   recipe = "boats:boat",
   burntime = 20,
})
